United Nations agencies and humanitarian organizations on Tuesday launched a fresh appeal for 1.6 billion dollars in order to prevent a catastrophe in the food-strapped Sahel region of West Africa, according to dpa. The most-affected countries are Burkina Faso, Mali, Chad, Niger and Mauritania, where UN officials said the situation has "deteriorated dramatically through 2012," because of a "lethal combination" of drought, poor harvest, rising food prices and displacement. "It is crucial that momentum be maintained in the months to come, not only to address critical needs but also to prepare for rebuilding lives and livelihoods of people affected by the crisis," said David Gressly, the UN regional humanitarian coordinator for the Sahel. In Niger, there has been an 18-per-cent increase in the number of affected people since January. An estimated 6.4 million are now severely affected by a lack of food and water. Some have resorted to raiding anthills and termite mounds in search of grain. "The crisis is already desperate and is getting worse," said Britain's International Development Minister Stephen O'Brian, who was in Niger Tuesday to see the extent of the crisis. "Now is the time for others in the international community to step up," he said, adding that Britain "will not sit back while children starve to death in the Sahel." Britain has pledged funds to help 1.4 million people in the region. On Monday, European Union countries and international partners pledged to funnel an extra 940 million euros (1.2 billion dollars) into the region, where a total of 18 million are said to be at risk.